Elevating platform structure



June 12, 1956 H. B. MIDDENDORF ELEVATING PLATFORM STRUCTURE 2 Sheets-Sheet 1 Filed May 7, 1952 INVENTOR. fi E/v/Qy B Mioomom:

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flnvny B- HIDDENDORF BY flaw, Mil-0 United States Patent ELEVATING PLATFORM STRUCTURE Henry B. Middendorf, Pittsburgh, Pa., assignor to Scaffold Equipment Company, Pittsburgh, Pa., :1 corporation of Pennsylvania Application May 7, 1952, Serial No. 286,455

1 Claim. (Cl. 304-29) This invention relates to portable elevating platform structures, such as are used in servicing airplanes, where the platforms can be raised to any desired height within certain limits.

In the interest of strength, simplicity and compactness, it is desirable to provide elevating platform structures with telescoping legs. However, if the platform is to be raised very far above its lowest position, telescoping legs have not provided a rigid enough structure for the elevated platform. This is because the inner or movable legs have had too great an unbraced length above the outer or stationary legs. Any braces between the inner legs would have prevented them from descending the desired distance into the outer legs.

It is among the objects of this invention to provide an elevating platform structure which has telescoping legs that can be fully telescoped when the platform is in its lower position, and in which the inner legs are adequately braced when the platform is in its upper position. Other objects are to provide such a structure in which the platform can be raised by a hydraulic jack operated by a man on the platform, in which a ladder is provided that increases in height as the platform is raised, and in which the legs slant forward to permit the front of the platform to be placed close to the work.

In accordance with this invention, a group of stationary tubular legs are rigidly mounted on a base and extend upward from it in parallel relation. Each of the legs is provided with a slot in a side facing another of the legs, with the slot extending downward from the upper end of the leg. Stationary braces are attached to the outside of the legs to form a rigid structure. A sliding leg is telescoped into each slotted leg, from the upper end of which it projects. A platform is mounted on the upper ends of the sliding legs. Bracing extends through the leg slots and rigidly connects the sliding legs. The platform is raised by any suitable means, preferably by a hydraulic jack connecting the center of the platform to the center of the base. When the platform is raised, the sliding legs slide upward in the slotted legs and the bracing moves out of the slots and braces the sliding legs above the slotted legs. At one end of the base there is a ladder formed from a section attached to the slotted legs and another section connected with the platform, so that the upper section will move up and down with the platform. Preferably, the legs and ladder slant forward.

The preferred embodiment of the invention is illustrated in the accompanying drawings, in which Fig. 1 is a side view of my elevating platform structure; Figs. 2 and 3 are fragmentary horizontal sections taken on the lines II-II and IIIlII, respectively, of Fig. 1; Fig. 4 is a reduced side view of the structure showing the platform elevated; and Fig. 5 is a view of the rear or ladder end of the elevated structure.

Referring to the drawings, a base is formed from a rectangular frame 1 provided with a cross member 2 closer to its rear end than to its front. Mounted on the corners of the frame are vertical sleeves 3 in which casters ice 4 are swivelled to permit the base to be moved from one location to another. Rigidly mounted on the rear corners of the base are two tubular members 6, which preferably are rectangular in cross section. These two members form the stationary rear legs for the platform. Parallel to these legs there are two more like tubular legs 7, which are rigidly mounted on the opposite sides of the base about halfway between cross member 2 and the front end of the base. All of these legs are parallel to one another, and they preferably are inclined forward. The front legs are connected to the legs behind them by horizontal upper braces 8 and central braces 9, and by upper and lower diagonal braces 11 and 12. The upper ends of the front pair of legs 7 are braced by inclined braces 13 extending therefrom down to the front corners of the base. These inclined braces are reinforced by crossed diagonal braces 14.

Telescoped into each of the stationary legs is a sliding leg 16, which likewise can be formed from a rectangular tube. The upper ends of the sliding inner legs project only far enough from the tops of the stationary outer legs to permit the inner legs to be fastened to a rectangular platform 17 which preferably projects a short distance forward from the front legs. The opposite sides of this platform may be provided with guard rails 18. To raise the platform, a long piston 19 and cylinder 20 are connected to the center of the base cross member 2 and to the bottom of the platform. Preferably, the cylinder is connected to the platform so that a hose 21 can be connected to the upper end of the cylinder and extend up to hydraulic pumping unit 22 mounted on the platform. This unit is operated manually by a handle 23 to pump fluid into the top of the cylinder above the piston in order to raise the platform. As the platform rises, the inner legs 16 slide upward in the lower legs.

It is a feature of this invention that the lower legs do not have solid side walls, but are provided with slots 26 extending downward from their upper ends. These legs preferably have their wide side walls parallel to the sides of the base, in which case the slot in each leg is in its inner wide side wall so that the rear leg slots face each other and the front leg slots face each other. These slots permit the inner legs 16 to be rigidly connected by front and rear cross braces 27, because such braces can extend through the slots and be welded to the legs inside the slotted legs. Any desired number of cross braces can be used at vertically spaced intervals along the legs. To further strengthen the inner legs, the front and rear cross braces are connected by parallel longitudinal braces 28 which straddle the hydraulic cylinder 20, as shown in Fig. 2. When the platform is raised, cross braces 27 move upward in slots 26 and leave the lower legs, as shown in Figs. 4 and 5. The long length of legs 16 above the lower legs are rigidly braced by braces 27 and 28, so that the whole structure remains rigid and steady. Due to the forwardly slanting legs, the platform overhangs the front portion of the base, which permits the platform to be moved in closer to airplane nacelles than otherwise. When the platform is lowered again, cross braces 27 slide back down into slots 26 so that the legs can be fully telescoped.

At the back of the structure there is a ladder to permit workmen to climb up to the platform. This ladder is formed in two sections which are slidably connected to gether so that it will expand and contract as the platform is moved up and down. The lower section is fastened to the stationary rear legs 6. It has side rails that are in the form of outwardly facing channels 31. The channels are connected by the steps 32 of the ladder, which may pro ect rearwardly from the rails but do not project forward. Welded to each channel near its upper and lower ends are rods 33 that extend outward and then curve backward toward the rear legs. The front ends of these rods are bolted to plates 34 projecting from the sides of the outer legs 6. Thus, the lower section of the ladder is supported by these four curved rods, and the rods and ladder help to brace the rear legs. Hand rails 35 can be welded to the sides of the lower ladder section.

The upper section of the ladder also has side rail channels 37, the upper ends of which are secured to brackets 38 projecting from the back of the platform. Welded to the lower ends of these channels are brackets 39 which hook around the front flanges of lower channels 31, along which they can slide when the platform is raised and lowered. The upper channels 37 are connected by ladder steps 41 which may project forward from them but which do not project rearwardly to avoid catching on steps 32. The upper channels also can be provided with laterally projecting hand rails 42 that can move down between the rods 33 that support the lower section of the ladder, as shown in Figs. 1 and 3. Due to the inclination of the platform legs, the ladder also is inclined, which makes it easier to use than a vertical ladder.

According to the provisions of the patent statutes, I have explained the principle of my invention and have illustrated and described what I now consider to represent its best embodiment. However, I desire to have it understood that, within the scope of the appended claim, the invention may be practiced otherwise than as specifically illustrated and described.

I claim:

An elevating platform structure comprising an elongated rectangular base having front and rear ends, a pair of tubular legs rigidly mounted on the rear end of the base, another pair of legs rigidly mounted on the base at points spaced from the front end of the base, all of said legs being inclined forward and being parallel to one another, each of the legs being provided with a slot in the side facing the leg across the base from it and extending downward from the upper end of the leg, braces extending from the front end of the base upward to the upper portions of the front 7 legs and attached thereto, braces rigidly connecting the back legs to the front legs, a sliding leg telescoped into each slotted leg and projecting from its upper end, a cross brace extending through the slots in said front legs and fastened to the sliding legs therein, a cross brace extending through the slots in said rear legs and fastened to the sliding legs therein, bracing rigidly connecting said cross braces, a platform mounted on the sliding legs, an inclined stationary ladder section rigidly connected to said rear legs and spaced therefrom, an inclined sliding ladder section rigidly connected to the rear of said platform and extending down between said stationary ladder section and the adjacent legs, means slidably connecting the lower 1 end of the sliding ladder section to the stationary ladder section, and means for raising the platform, whereby said sliding legs will slide upward in the slotted legs and the sliding ladder section will slide up the stationary ladder section to form an inclined ladder from the base to the elevated platform.

References Cited in the file of this patent UNITED STATES PATENTS 69,168 Blomgren Sept. 24, 1867 589,244 Cantore Aug. 31, 1897 619,439 Riecke Feb. 14, 1899 1,116,091 McDonald Nov. 3, 1914 1,595,450 Christian Aug. 10, 1926 1,639,962 Pfitfner Aug. 23, 1927 1,981,680 Tindale Nov. 20, 1934 2,062,473 Norton Dec. 1, 1936 2,183,679 Hillis Dec. 19, 1939 2,204,671 Erickson et al. June 18, 1940 2,531,001 Short Nov. 21, 1950 2,610,875 Wheeldon Sept. 16, 1952 FOREIGN PATENTS 22,375 Great Britain 1900 294,434 Great Britain July 26, 1928 

